Devices such as electronic devices with displays and solar cells need light-transmitting protective members to protect their surfaces. Among these devices, flexible displays and flexible solar cells have recently been used. Since thick glass plates cannot be used in such flexible devices, the flexible devices need alternatives to such thick glass plates as protective members.
As such protective members, protective members for solar cells are conventionally proposed (Patent Literatures 1 and 2). Patent Literature 1 discloses a protective film in which a deposited silicon oxide film formed by the CVD method and a deposited silicon oxide film formed by reactive ion cluster beam deposition are stacked on a fluorine-containing resin film. Patent Literature 2 discloses a protective sheet including a plastic film, and a first inorganic layer, an organic layer and a second inorganic layer that are stacked on the plastic film.
The barrier properties are important in protecting a device. In particular, a flexible device needs a flexible protective member with high barrier properties. Patent Literature 3 discloses an example of a barrier layer having barrier properties.